Stepping mechanism for teleprinter

ABSTRACT

A high speed teleprinter with a wire matrix print head synchronously stepped across the page, advanced by a pair of continuously reciprocating racks, and one stationary rack, cooperating with selectively operable pawls mounted on the print carriage, and controllable by the print signals. A paper feed mechanism, as an integral part of said teleprinter, which cooperates with the continuously reciprocating racks for the indexing of the surface to be printed. A ribbon feed shuttle mechanism, as an integral part of said teleprinter, which cooperates with the continuously reciprocating racks for the continuous lateral movement of the print ribbon.

United States Patent Drillick June 25, 1974 [5 STEPPING MECHANISM FOR 2,465,657 3/1949 Norton 197/84 A TELEPRI 2,524,854 10/1950 2,701,045 2/1955 [75] Inventor: Jacob H. Drillick, l-lackensack, NJ. 3,3 ,215 1/1968 [73] Assignee: International Teleprinter Corporation, Carlstadt, NJ. 1 52 10/1970 1221 Flledi 1972 FOREIGN PATENTS OR APPLICATIONS [21] Appl. No.: 224,159 1,529,888 5/1968 France 197/85 1,436,740 5/1969 Germany 197/82 [63] Continuation-in-part of Ser. No. 41,514, May 28,

1970, abandoned.

52 us. c1 197/82, 178/28, 197/133,

197/151 [51] Int. Cl B4lj 19/00 [58] Field 01 Search 197/60, 82, 84 R, 84 A, 197/84 B, 85, 86, 87, 88, 89, 91, 92, '93, 133, 151; 178/28, 29, 32, 35, 38, 39, 40, 41

[56] References Cited UNITED STATES PATENTS 458,567 9/1891 Frankey 197/89 460,328 9/1891 Wright 178/29 616,888 1/1899 Brown 197/60 1,174,696 3/1916 1,178,215 4/1916 1,832,160 11/1931 2,030,081 2/1936 Wells 197/84 A X Related US. Application Data Primary ExaminerErnest T. Wright, Jr.

[5 7] ABSTRACT A high speed teleprinter with a wire matrix print head synchronously stepped across the page, advanced by a pair of continuously reciprocating racks, and one stationary rack, cooperating with selectively operable pawls mounted on the print carriage, and controllable by the print signals. A paper feed mechanism, as an 2 Claims, 18 Drawing Figures PATENTEDJUNZSIBH SHEEI 01 W10 PATENTEUJUNZSIBH saw on 0F 10 PATENTEDJUNZSIQM PATENIEDJUN25I974 V 3.819.028

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sum over 1o PATENTEBJUNZSIHH sum -09 or 10 STEPPING MECHANISM FOR TELEPRINTER CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of my prior U.S. Pat. application Ser. No. 41,514, filed May 28, 1970, entitled Serial Printer. The prosecution of the invention in that application was abandoned on Feb. 15, 1972, in favor of the further prosecution of the invention in the present application.

FIELD OF INVENTION The invention here disclosed has general applicability to any high speed printer, and particular applicability to printers, which receive signals at random intervals asynchronously, as generated, rather than at regular synchronous intervals.

DESCRIPTION OF THE PRIOR ART Teleprinters were developed nearly one hundred years ago to replace the need for telegraph operators to manually send and manually receive telegraph messages. The first teleprinters generated a signal for each character as typed, and could not send another signal until that character had been printed by the receiving machine. The receiving teleprinter had to receive and decode the signal, select the print character, operate the print mechanism, and then space the carriage one position.

To allow faster transmission of messages, teleprinters were developed to allow an operator to record the mesv SUMMARY OF THE INVENTION The present invention is an improved stepping mechanism allowing the operation of the teleprinter at up to 30 characters per second. This higher speed is possible, because, unlike prior machines, the driving mechanism is continuously operated and the character index signal need only operate a mechanical element just large enough to engage the already reciprocating driving mechanism, transmitting the power to index the print carriage.

DRAWING The teleprinter printer will be further described with reference to the attached drawing, wherein like numbers indicate like parts throughout the drawing.

The complete teleprinter is shown in a perspective view in FIG. 1.

The printer with the housing removed is shown in perspective in FIG. 2.

The printer is shown in plan view with the housing removed in FIG. 3.

FIG. 4 shows the printer in front sectional view in a The printer is shown in a vertical side sectional view in FIG. 5, the view taken along section line 5-5 of FIG. 2.

FIG. 6 is a fragmentary detailed perspective view of the operating cam shaft showing the two print head carriage advancing cams, and the ribbon feed cam.

FIG. 7 is a schematic cross-sectional view taken in front of the two print head carriage advancing cams, to illustrate the method of reciprocating the two flat print head carriage advancing racks in phase.

One of the solenoid controlled carriage advance pawls is shown in FIG. 8, which is a fragmentary detailed sectional view taken on section line 88 of FIG. 3.

The one stationary rack and two reciprocating racks, together with the three cooperating pawls are shown in FIG. 9, which is a fragmentary perspective view, illustrating the continuous reciprocation of the two racks, and the controlled positioning of each of the three pawls.

The print carriage control system, including the roller mounts and spring return, is shown'in FIG. 10, which is a vertical section view taken along section line 10-10 of FIG. 8.

The paper advance shaft is shown in FIG. 11, which is a vertical section view taken along section line 11-11 of FIG. 4.

FIG. 12 is a horizontal split'sectional top view show ing the return spring for a dash pot not shownwhich engages fixed piston 49 and associated mechanisms taken on section line 12-12 of FIG. 4.

The paper advance mechanism is shown in plan in FIG. 13 and vertical section in FIG. 14.

The ribbon feed mechanisms are shown in FIG. 15.

FIGS. 16 is a schematic view of an earlier version of the stepping mechanism;

FIG. 17 is a sectional view taken on line l7l7 of FIG. 16; and,

FIG. 18 is a block diagram of the electronic logic.

DESCRIPTION OF PREFERRED EMBODIMENT The major components of the teleprinter are illustrated in FIGS. 1 and 2. The complete printer has a stand 20, a printer base 21, a printer cover 22, and is shown with paper roll 23, keyboard 24, electic motor 25, matrix printer 26, and ribbon feed mechanism 27.

MOVEMENT OF THE PRINT HEAD CARRIAGE The mechanical components and arrangement for the operation of the movement of the print head carriage 33 will be explained with reference to FIGS. 3 through 11.

The teleprinter has a conventional matrix printer 26, which prints a 5X7 matrix. There are seven vertically aligned print rods 31, operated by sevenhorizontally spaced print rod solenoids 32, mounted on print head carriage 33.

The print head carriage 33 is mounted on the teleprinter base 21 by 10 roller bearings 34, operating on a pair of guide rods 35, as illustrated in FIG. 10. These roller bearings 34 and guide rods 35 allow the print head carriage 33 to traverse the page to be printed, and

prevent either vertical or lateral movement of the print head carriage 33.

As shown in FIG. 4, a print head carriage return spring 36, passing over a vertical pulley 37, and hrizontal pulley 37A, has one end attached to the print head carriage 33 and the other end attached to the base 21. The print head carriage 33 is biased by the return spring 36 toward the left hand margin.

Depending from the print head carriage 33 are three two core solenoids 38, 39 and 40. Beneath each of the solenoids 38, 39, 40 are pawls 41, 42 and 43, shown from the rear in FIG. 10, and fragmentarily shown in FIG. 9.

Each of the pawls 41, 42, 43 is pivoted on journal 42A, which is rigidly attached from a depending structure 44, from the print head carriage 33. Each of the pawls 41, 42, 43 acts as an armature for its associated solenoid 38, 39, 40, and each is biased downwardly by springs 45, 46 and 47.

Electronic control cable 48, illustrated in FIG. 2 carries control signals to selectively operate each of the print rods 31 in the matrix printer 26, and to selectively energize each of the carriage pawl solenoids, 38, 39, 40, thus selectively lifting each of the pawls 41, 42, 43.

Three toothed racks, 51, 52 and 53 are provided heneath each of the pawls, 41, 42, and 43 and cooperating with the tip of each pawl 41, 42, 43 when the tip is in the released position. The two racks 51 and 52 nearer the front of the machine continuously reciprocate over a distance of one character width, while the rack 53 is stationary.

Motor 25 and motor drive shaft 136 in cooperation with a pulley system comprising motor drive pulley 130, drive belt 132, and cam shaft pulley 131, continuously rotates drive shaft 54 mounted on support member 137, and drives cam 55 acting with rack 51, and cam 56 operating with rack 52 as illustrated in FIG. 3.

Racks 51 and 52 are biased by springs 98 and 99 (FIG. 13) against their associated print head carriage advancing cams 55 and 56 and therefore reciprocate continuously and, due to the arrangement of print head carriage advancing cams 55 and 56, exactly 180 out of phase with each other.

The print signal coming into the machine may require any one of four movements of the print head carriage 33. The signal may require the print head carriage 33 to move from left to right continuously across the page, and may require it to return to the left hand margin, or may increment or step the print head carriage 33 character by character, either forwards or backwards, that is, to the right or to the left.

Prior to receipt of a signal the matrix printer 26 is held at any given character position by lifting pawls 41 and 42, from reciprocating racks 51 and 52. To accomplish this, solenoids 38 and 39 are energized. Pawl 43,

. on the other hand, is biased in its downward position,

where it engages stationary rack- 53. This prevents movement of the print head carriage 33 to the left, and return spring 36 prevents movement of the print head carriage 33 towards the right.

When a signal requires continuous movement of the print head carriage 33 across the page to the right margin, all three pawls 41, 42, and 43 are released. Pawls 41 and 42, in sequence engage reciprocating racks 51 and 52, advancing the print head carriage 33. When pawl 41 is advancing the print headcarriage 33, rack 52 is retracting and pawl 42 bounces over two teeth. Pawl 43 bounces over one tooth of fixed rack 53.

When a print head carriage return signal appears, all three pawls, 41, 42 and 43 are lifted and the print head carriage 33 now returns to the left under the influence of return spring 36. The print head carriage 33 is slowed at the end of its travel by a conventional pneumatic dash pot not illustrated in the drawing and attached to the bottom of print head carriage 33 and engaging fixed piston 49 engaging fixed piston 49, as illustrated in FIG. 3.

Incoming print signals are received in random order and are quite regularly received while the machine is executing a previous print instruction. Since the machine cannot print the second character while printing the first, signals are stored in a conventional temporary buffer memory 48A also called a logic box 'in the electronic art and controlled by conventional electronic logic, which is shown in FIG. 18. The electronic circuitry, capable of accepting incoming signals at random intervals and the storage of the signals in a buffer memory 48A, is well known in the art and requires no further amplification.

The beginning of each print head carriage advance cycle is detected through a timing wheel 57 attached to the drive shaft 54. The position of the timing wheel 57 is read by a magnetic sensor 58.

.At the beginning of each cycle, the storage buffer memory 48A is searched for the next print signal. When the print signal to print a character is sensed, the pawl 41 or 42 associated with the advancing rack 51 or 52 is released by de-energizing its associated solenoid 38 or 39. The pawl 41 or 42 engages the ratchet tooth on its associated rack 51 or 52 causing the print head carriage 33 and matrix printer 26 to step across one character position.

As the matrix printer 26 is moved across that character position, selected print rods 31 are activated at each of five firing points.

By way of example, for a five by seven matrix printing, the character L, all seven printing rods 31 are fired at the first point, and only the lowest printing rod 31 is fired at each of the four subsequent points.

After the character has been printed, and the reciprocating rack 51 or 52 which has been engaged has moved to its maximum right position, stationary pawl I 43, which is also depressed against its rack 53, will engage in the next tooth of rack 53 and will hold the print head carriage 33 in that position as the reciprocating rack 51 or 52 retreats. As this happens, the solenoid 38 or 39 associated with the retreating rack 51 or 52 will energize, raising the pawl 41 or 42.

When a signal is received to backspace the print head carriage 33 one position, the pawl 41 or 42 associated with the reciprocating rack 51 or 52 moving to the right is released. As that rack 51 or 52 advances, no movement occurs until the very end of the movement to the right. The rack 51 or 52 actually moves a very small amount beyond the character position, so that the print head carriage 33 is slightly moved by the newly engaged pawl 41 or 42 and the pawl 43 on the stationary rack 53 is free to lift by energization of solenoid 40. As the printhead carriage 33 is now held by the pawl 41 or 42 on the retreating rack 51 or 52, it is moved to the left, and after stationary rack pawl 43 has cleared the previous tooth, its solenoid is de-energized and the pawl 43 is released, engaging that rack 53.

The reciprocating rack 51 or 52 continues slightly past the beginning of the character position, so that its pawl 41 or 42 is released and lifted by energization of its solenoid 38 or 39 The three rack system as shown allows continuous and rapid movement of the print head carriage 33 in either direction. A printer could be designed, however, utilizing the present invention, with only two racks, one stationary and one moving, which would index the print head carriage 33 only during half of a rack movement cycle.

FIGS. 16 and 17 disclose the stepping mechanism as disclosed in my above-mentioned prior application. The theory of the mechanism is the same and corresponding elements are apparent and are not here further described.

PAPER FEED MECHANISM The spool of paper 23 is carried on freely rotating rod journaled in paper shaft bracket 134 integrally connected to bracket frame 135, attached on base 21, as illustrated in FIG. 3. The movement of the paper 23 will be further described with reference to FIGS. 10, 11, 12, 13 and 14.

The paper 23 follows the path of the arrows in FIG. 10, underneath paper roll 77, and is pressed against form 72, by flexible shield 73. As the paper 23 passes matrix printer 26 the form 72 is indented to support the platen 74.

The paper roller 77, includes a shaft 80, a detent wheel 81, a manual handle 82, shown in FIG. 3, bevel gear 83, pin wheels 84 and pressure rollers 85. Paper roller 77, detent wheel 81, manual handle 82, bevel gear 83, pin wheels 84, and pressure rollers 85, are all mounted on shaft 80.

The paper roller shaft is geared to shaft 86, on one end of which is bevel gear 87, cooperating with the bevel gear 83 of the paper roller shaft 80.

On shaft 86 are two circular ratchets 88. As shown in the top plan view of FIG. 12, the ratchets 88 have teeth pointing towards the machine, allowing counterclockwise revolution of shaft 86, as viewed from the front of the machine.

As shown in FIG. 14, each circular ratchet 88 has associated therewith a pawl 90 controlled by solenoid 91. The pawl 90 is spring biased to engage the ratchet 88, and is disengageable by energizing the solenoid 91. Each of the pawls 90 and solenoids 91 is fixed to the right end of movable racks Sland 52, respectively.

When the teleprinter is printing a line of data, both of the pawls 90 will be continuously disengaged by their respective solenoids 91, so that although they reciprocate, shaft 86 does not move.

When a paper advance signal is received, one of the continuously reciprocating solenoids 91 is deenergized, engaging its pawl 90 with ratchet 88. This ratchet 88 then rotates shaft 86. The shaft 86, through bevel gears 87 and 83, rotates the paper roller shaft 80, indexing the paper 23 one line, and the reciprocating solenoid 91 re-energizes, withdrawing the pawl 90, thus stopping the paper movement.

Paper roller 77 is maintained in a stationary position between indexing of the paper 23 by detent wheel 81. Detent element 163 cooperates with the teeth of detent wheel 81 to maintain the stationary position of paper 23. Detent element 163 is biased to cooperate with the teeth of detent wheel 81 by spring 162. Pressure roller 165 is disengaged to facilitate the feeding of paper 23 by pressure roller disengagement member 161. The dis- 5 engagement of the pressure roller disengagement member 161 being accomplished by movement of lever arm 160, which is connected to the pressure roller disengagement member 161 at pivot point 164.

RIBBON FEED MECHANISM The mechanisms operating the ribbon feed will be described with reference to FIGS. 2, 6, and 15. A left and right hand pair of ribbon spools and are mounted on stationary axes, at either end of the printing area. A non-continuous ribbon 97 feeds from one spool 100 or 110 to the other and back again, across the face of matrix printer 26, through suitable roller guides 11.

Each spool 100, 110 has a detector arm 101 and 111, which senses the amount of ribbon 97 left on the spool 100, 110. The detector arm 101, 111 is pivoted and biased by springs 102 and 112, against the ribbon 97 on the spool 100, 110.

When the ribbon 97 has been fed from the spool 100, 1 10, the foot of arms 101 and 1 11 will actuate switches 103 or 113.

When one of the switches 103, 113 is actuated, it electronically sets a conventional flipflop switch memory not illustrated, to energize the associated ribbon feed solenoid 104 or 114, engaging links 105 or 115.

Operating off of main drive shaft 54 is ribbon feed cam 120, against which is biased pivot arm 121 as shown in FIG. 6. Pivot arm 121 continuously reciprocates ribbon feed shuttle 122 through a connection at pin 123. As illustrated in FIGS. 6 and 15, pivot arm 12] is perpendicular to the ribbon feed shuttle 122 at connection pin 123.

The ribbon feed shuttle 122 reciprocates in bifurcated slides 124 and 125, and is biased against links 105 and by springs 106 and 116. The two links 105, 115 are themselves forwardly biased by springs 107 and 117.

When neither solenoid 104 nor 114 mounted on support members 143 is energized, the ribbon feed shuttle 122 will oscillate freely. When one of the solenoids 104 or 114 is energized, say 104, then the left ratchet tooth 109 of shuttle 122 will be drawn into engagement with the teeth of ratchet wheel 108 thus winding the ribbon 97 from the right hand spool 110 to the left hand spool 100. When ratchet tooth 109 of shuttle 122 is reciprocating to the next ratchet tooth of ratchet wheel 108, ratchet wheel 108 is held stationary by ratchet wheel pawl 140. Ratchet wheel pawl is biased to engage ratchet wheel 108 by spring 141 which is attached to solenoid 104 at pin 142. When solenoid 104 is energized ratchet wheel pawl 140 engages the teeth of ratchetjwheel 108. Ratchet wheel pawl and spring 151 attached at pin 152 operates in a like manner when solenoid 114 is energized as illustrated in FIG. 15. When detector 111 senses an absence of ribbon 97 on the right hand spool 110, it will engage switch 1 13, energizing solenoid 114, drawing down the shuttle 122 while solenoid 104 will be de-energized, thus releasing the shuttle 122 away from ratchet wheel 108. The shuttle 122 will engage the teeth of ratchet wheel 118, winding the ribbon 97 onto the right hand spool 110.

Having described but one embodiment of my invention as required by law, I claim:

1. In an automatic teleprinter capable of receiving asynchronous electronic pulses representing characters the combination comprising:

a. a character printing mechanism;

b. electronic control for said character printing mechanism responsive to said electronic pulses representing characters;

c. said printing mechanism mounted on guide means for lateral movement of said printing mechanism across a surface to be printed;

d. a plurality of rachet tooth racks;

e. said racks being parallel to said guide means and cooperating with said printing mechanism;

f. one of said racks being stationary;

g. means to continuously reciprocate at least one of said racks in a stroke of one character space in a direction parallel to said guide means;

h. a pawl for each rack, pivotally attached to said printing mechanism;

i. each of said pawls in an extended position, engaging the teeth of a respective rack;

j. a solenoid for each of said pawls controlling the engagement of said pawls with said racks;

k. electronic circuitry to accept incoming character signals at random intervals;

1. said circuitry storing said signals in a buffer;

ml said circuitry accessing said stored signals in synchronism with said continuously reciprocable rack;

of racks comprise three racks including a pair of racks reciprocable out of phase. 

1. In an automatic teleprinter capable of receiving asynchronous electronic pulses representing characters the combination comprising: a. a character printing mechanism; b. electronic control for said character printing mechanism responsive to said electronic pulses representing characters; c. said printing mechanism mounted on guide means for lateral movement of said printing mechanism across a surface to be printed; d. a plurality of rachet tooth racks; e. said racks being parallel to said guide means and cooperating with said printing mechanism; f. one of said racks being stationary; g. means to continuously reciprocate at least one of said racks in a stroke of one character space in a direction parallel to said guide means; h. a pawl for each rack, pivotally attached to said printing mechanism; i. each of said pawls in an extended position, engaging the teeth of a respective rack; j. a solenoid for each of said pawls controlling the engagement of said pawls with said racks; k. electronic circuitry to accept incoming character signals at random intervals; l. said circuitry storing said signals in a buffer; m. said circuitry accessing said stored signals in synchronism with said continuously reciprocable rack; n. means for a character signal to control the operation of the solenoid associated with the pawl associated with the rack which first commences an advance stroke following receipt of said character signal; o. said continuously reciprocable rack during an advancing stroke incrementing said character printing mechanism one character position; and, p. means for a character signal to activate the printing mechanism to print a character.
 2. The combination of claim 1 in which said plurality of racks comprise three racks including a pair of racks reciprocable 180* out of phase. 